From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 25 Jun 2007 01:06:45 -0700 (PDT) Received: from smtp.sauce.co.nz (smtp.sauce.co.nz [210.48.49.72]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l5P86bdo032264 for ; Mon, 25 Jun 2007 01:06:38 -0700 Received: from [192.168.4.111] (unknown [192.168.4.111]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp22.sauce.co.nz (Postfix) with ESMTP id 2506028825B for ; Mon, 25 Jun 2007 12:59:57 +1200 (NZST) Message-ID: <467F144F.3020804@sauce.co.nz> Date: Mon, 25 Jun 2007 13:03:11 +1200 From: Richard Scobie MIME-Version: 1.0 Subject: sunit-swidth parameters Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: xfs@oss.sgi.com I am under the impression that mkfs.xfs is able to obtain details from the Linux md subsystem, such that it will automatically create the optimal sunit and swidth parameters, to suit an md RAID array on which the filesystem is being created. Please correct me if I am wrong. If this is the case, then I am a little confused by the following: mkfs.xfs -f -l logdev=/dev/md1,size=10000b /dev/md5 meta-data=/dev/md5 isize=256 agcount=32, agsize=7630656 blks = sectsz=4096 attr=0 data = bsize=4096 blocks=244179840, imaxpct=25 = sunit=64 swidth=128 blks, unwritten=1 naming =version 2 bsize=4096 log =/dev/md1 bsize=4096 blocks=10000, version=1 = sectsz=512 sunit=0 blks realtime =none extsz=524288 blocks=0, rtextents=0 This is the output where /dev/md5 is a 3 disk RAID5, with a chunk size of 128kB. After reading the man page and looking at some examples in the mailing list archives, I would have thought that the best sizes would have been sunit=32 and swidth=64, or am I wrong? I ask, as I am about to resize this array by adding another drive and am trying to work out the new values for these parameters, to pass to mount - the values I have come up with are sunit=256 and swidth=768. Thanks, Richard